Once a primary tumor has metastasized and is clinically detectable by current diagnostic measures, treatment of the tumor becomes more complicated, and generally speaking, survival rates decrease. Consequently, it is advantageous to determine which tumors are more likely to metastasize and to advance the time to detection of metastasis, so that appropriate treatment may be started as soon as possible. Many different types of tumors are capable of metastasizing. Melanomas, in particular, are capable of aggressive metastasis.
Melanoma is a malignant tumor of melanocytes, and may occur in the eye (uveal melanoma), on the skin, or on mucosal tissues. Uveal melanoma is the most common intraocular malignancy. The incidence of this tumor increases with age and reaches a maximum between the 6th and 7th decade of life. Approximately 50% of patients die of metastases, a proportion that, despite all efforts to improve treatment, has remained constant during the last century. The average life expectancy after diagnosis of metastases is 7 months.
Around 160,000 new cases of melanoma of the skin are diagnosed worldwide each year, and according to the WHO Report about 48,000 melanoma related deaths occur worldwide per annum, which accounts for 75 percent of all deaths associated with skin cancer. Similar to uveal melanoma, when there is distant metastasis, the cancer is generally considered incurable. The five-year survival rate is less than 10%, with a median survival time of 6 to 12 months. Additionally, specific to uveal melanoma and cutaneous melanoma and generally considered for carcinoma, earlier treatment of malignancies is associated with improved progression-free and overall survival.
Due to the aggressive nature of these malignancies, there is a need in the art for methods of predicting the risk of metastasis and for earlier detection of metastatic disease, so that treatment may begin as early as possible.